Remote control system for radioreceivers



y 1932, A. s BLATTERMAN 1,356,310

REMOTE CONTROL SYSTEM FOR RADIOHECEIVERS Filed March 31, 1950 4Sheets-Sheet l 7 1 I a 155% .6 1;- 1) 'f/ JdjTL-B :wwmtwflLberiS.BlaiiBrnwr/w,

May 3,1932. A. s. BLATTERMAN 1,856,310

REMOTE CONTROL SYSTEM FOR RADIORECEIVERS Filecl March 31, 1950 4Sheets-Sheet 2' I i W m /"--l g T0 LIGHTLINES .26

T0 LIGHT LINES A m PAD/0 RECEJVER 1/71 beri 5.1?la1l'er'rnan A s.BLATTERMAN 1,856,310

REMOTE CONTROL SYSTEM FOR RADIORECEIVERS May $511, 193?.

Filed Mafch :51, 193 4 Sheets-Sheet 3 May 3, 1932.

A. 5. BLATTERMAN REMOTE CONTROL SYSTEM FOR RADIOHECEIVERS 4 Sheets-Sheet4 Filed March 31, 1930 u m M Patented May 3, 1932 UNITED STATES ALBERTS. BLATTERMAN, OI ASLBUBY PARK, NEW JERSEY REMOTE CONTROL SYSTEM FORRADIOBECEIVERS Application filed March 31, 1930. Serial No. 440,594.

This invention relates to a system for the remote control operation ofradio receivers without the use of auxiliary wires between the radioreceiver and the remote control a point.

A primary object of the invention is to provide a novel system of remotecontrol operation of broadcast receivers furnished with power from theusual house service lighting in lines, without in any way altering thereceiv ing set itself, thus rendering the invention adaptable for use inconnection with any standard light socket power operated receiving set.That is to say, the operator of the set to can, without in any wayaltering or changing the mechanical or electrical construction of thereceiver operate the same from any point in the house or building whoseservice lines supply power for operating the vacuum 1% tubes. In thatconnection the invention provides means by which radio signals which itmay be desired to reproduce through the usual radio receiving set can betuned in from a point other than at the set and with- 1333 outmanipulating the tuning apparatus of the set or mechanically operatingthe tuning up paratus.

More specifically the invention provides a system for the remote controltuning of a to radio receiver to any wave length, even though the wavelength be outside the normal wave length range of the receiver.

Another object of the invention is to provide a method and means forregulating the signal strength or so-called volume of the signalsreproduced on the receiving set from a point remote from the set itself.

A further object of the invention is to provide a method and means bywhich the radio receiver may be turned on or oil from the remote controlpoint without manual operation of the on and off switch of the set.

A still further and general object of the invention is to provide amethod and means by which the remote control operation of the radioreceiver may be accomplished by the use oi the power available in theelectric light or power lines which 't'urnish current to the usualservicr outlets.

lVith the'foregoing and other objects in View, the invention consists inthe novel features of construction, combination and arrangement of partsas will be hereinafter more fully described,illustratedin theaccompanying drawings and defined in the appended claims.

Similar reference characters designate corresponding parts through theseveral figures of the drawings.

Figure 1 is a diagram illustrating the essential elements and purpose ofthe invention.

Figure 2 is a View diagrammatically illustrating a standard broadcastreceiver and the remote control means associated therewith.

Figure 3 is a view illustrating diagranr matically one expedientutilized for the purpose of avoiding the undesirable effects of theusual ground connections in house lighting circuits which will permitthe proper functioning of the present remote control means.

Figure 3a illustrates diagrammatically the apparatus contained withinthe mixing box and the remote control box and an expedient utilized forthe purpose of avoiding the undesirable effects of the usual lamps andother appliances commonly connected to the house lighting circuits. v

Figure 4 is a view illustrating a form of mechanical relay or switchwhich may be used in the mixing box for opening and closing the circuitto the radio receiver.

Figure '5 is a diagrammatic view fully illustrating in diagrammatic formthe apparatus and circuit involved in the practice of the presentinvention.

Figure 6 is a diagrammatic View illustrating a modificatoin of theapparatus and circuits shown in Fig. 5.

Before proceeding to a detailed description of the functioning of thevarious parts of the apparatus comprising the present remote controlsystem, reference will first be made, by way of explanation, to thetheory and principles involved.

Referring to Figure 1, the usual radio receiver which may be of anystandard type receiving power from alternating house current servicelines is designated as R havin the usual antenna connection A and grcunconnection G. The receiver R is adapted to be connected in theconventional manner by a cord and plug R with a service outlet b of thepower lines L of the house lighting circuit which are connected in theusual manner through the switch L with the main power lines L whichsupply the usual current to the house for lighting the lamps L or otherdevices which may be connected in the usual manner with the servicelines L for house service. In other-words, Figure 1 of the drawingsillustrates diagrammatically a building lighting circuit havingaplurality of outlets or service plugs, to'one of which .the radioreceiver is connected forthe purpose of receiving power.

According to the present invention, when it is desired to operate theradio receiver ,R from a distant point, as for example another room inthe house, the control unit C having a cord and plug connection isadapted to be plugged in any of the service outlets or plugs so that theturning on and off of the radio receiver R as well as its tuning ma beeffected at will by the operator of unit a at any point in the house.

, Thus, it would be apparent that the present invention contemplates noother connection between the remote control unit C and the radioreceiver R, than that incidentally and the remote control unit to thecommon electric lighting circuit, and whereby the radio receiver may beturned on or off, and may be caused to reproduce radio signals of anywave length arriving on its antenna and also the operator may regulatethe volume or strength of such signals, at will, from the remote controlpoint.

Heretofore it has been necessary to use special auxiliary connectingwires between the remote control unit and the receiver for the purposeof (1) switching on and off, (2) tuning, and (3) the regulation ofsignal strength. This arrangement, however, requires. that the radio.receiver be specially built, or at least partially rebuilt in order topermit of the use of the remote control feature of operation.Furthermore, the present so-called remote control systems permit of-theremote control reception of only a certain few predetermined orpreselected transmitting stations and all other systems fail inproviding an exact tuning of the radio receiver by remote controlbecause such tuning is obtained by mechanical means in which there isalways lost motion, friction and wear of the moving parts.

According to the present invention, however, since there are noauxiliary connecting wires between the remote control unit and thereceiver, the latter does not have to be rebuilt, or especially built,but on the contrary may be a receiver of any standard or conventionaldesign while the tuning is exact and continuous through all wave lengthsnot depending on the mechanical movement of the tuning apparatus of thereceiver in any way.

As previously stated, there are three functions of complete remotecontrol operation of a radio receiver, viz, (l) tuning the receiver, (2)regulating the strength of the signal, and (3) switching the receiver onand off.

Method of tuning Referring first to the principle utilized in thepresent invention for performing the remote control tuning function, itmay be pointed out that this is accomplished by a unique use of thewell-known phenomenonof beats produced by two different frequencies ofelectric vibration being simultaneously impressed on a given circuit. Ageneral understanding of the manner in which this is accomplishedaccording to the present invention may be had by reference to Figure 2wherein the receiving set R, is shown as being connected to conductorcord and plug R with the electric light line service outlet S. Thereceiver R is as usual, provided with the antenna binding post 1 and theground binding post 2. These binding posts are connected to a smallauxiliary apparatus box designated generally as M. at the bindingafforded by the connection of both the set.

posts 3 and 4, the antenna A and the ground Gr being removed from theradio set and connected to a pair of binding posts 5 and 6 on the box M.The auxiliary apparatus box M is also connected to the service lines Lby means of the wires 7 and 8. The remote control unit C is alsoconnected to the house lighting circuit L by means of its two-conductorcord and standard plug C.

Theremote control unit G contains a high frequency oscillating vacuumtube to be later referred to more in detail. The frequency ofoscillation of this tube is controllable or adjustable by means of avariable condenser or inductance operated by a knob or dial on thecontrol box. The power required for the operation of the oscillatingtube is drawn from the electric light line to which he remote controlbox is connected, as heretofore stated. The high frequency energygenerated by the said oscillating tube in the control box C isimpressed, in a way to be described later, upon the electric light linesthrough their cord connected to the control box.

I have discovered that the electric light lines referred to herein havecertain electrical characteristics, and it will be suflicient at thispoint to say that I have found that,

with proper circuitarrangements, also to be described more in detaillater, the high frequency energy impressed upon the lines by theoscillating tube in the control box will travel over the lines to allpoints in the house ill] tit)

and thus reach the auxiliary apparatus box M through its line cord 7 8.

At the same time, the apparatus box M Will have impressed upon it thehigh frequency energy of the incoming radio waves impinging upon theantenna-ground system AG. Thus the radio wave frequency, arriving fromthe antenna, and the remote control box frequency arriving over theelectric light lines, may be superposed one upon the other in theauxiliary apparatus box M. If these two frequencies are thus superposedin a suitable way, one secures the well known phenomenon of electricalbeats, the heat frequency being equal to the difference between the twoindependent superposed frequencies. Thus, if a radio telephone ortelegraph program or massage impinges upon the antenna A and has afrequency of say 1,000,000 cycles per second, it will pass into theauxiliary apparatus box M. Then if the remote control box frequency at Cis adjusted to 1,500,000 cycles the beat frequency at M will be1,500,000 minus 1,000,000 or 500,000 cycles. 0n the other hand, if theremote control box frequency fed to M over the light lines is, say,1,800,000 cycles, then the beat frequency will be 1,800,- 000 minus1,000,000 cycles, the latter being the frequency arriving over theantenna A, or 800,000 cycles. By changing the frequency generated at theremote control point C, therefore, any signal frequency coming in on theantenna A can be changed in the apparatus box M to some other frequencyequal to the difference between the antenna signal frequency and thecontrol boxfrequency.

Now if the difference frequency or beat frequency is one to which theradio receiver ll is responsive, the said beat frequently will beamplified by the receiver which is con-.

nected to the box M, and the antenna signal now changed to a differentfrequency, will be reproduced by the receiver through its loud speakeror other indicating device. The box M will be hereinafter referred to asthe mix ing box because at least one of its functions is to mix theantenna signal frequency with the light line control box frequency topro duce a beat frequency of suitable value for amplication by the radioreceiving set.

if the receiving set R is once tuned to a certain wave length (orfrequency) and left fixed at that tuning point, any signal arriving' onthe antenna can be caused to be amplified and reproduced by the radioset by simply adjusting the remote control frequency to a value suchthat the difference between it and the antenna signal frequency producesa beat frequency equal to the frequency to which the radio receiver hasbeen left tuned. lhus, all signals arriving on the antenna may be tunedautomatically from the remote control point so as to be reproduced onthe receiver itself by manipulation of the variable condenser orinductance in the remote control box which regulates the frequencygenerated therein. As this condenser is rotated, one station after theotheris heard on the radio set. The tuning is exact since it iselectrically ac complished rather than mechanically. In the practicalapplication of the above described method of remote control tuning,there is a precautionary measure which must be taken and this is mostimportant when the signals which it is desired to receive are on closelyadjacent Wave lengths or frequencies and occupy a relatively Wide bandof wave lengths. This is the condition that exists in the reception ofusual American broadcast programs which at present utilize ninety-sevendifferent frequencies for transmission spaced l0, 000 cycles apart from1,500,000 cycles to 54:0; 000 cycles. The precaution referred to is thatthe receiving set itself must not be left tuned for the purpose ofremote control operation at or near to a frequency which it may bedesired to receive. For example, if the receiver is left tuned to afrequency of 7 50,000 cycles, then a 7 50,000 cycle broadcast ingstation signal will bepassed directly through the mixing box M, Figure2, and be amplified by the receiver. At the same time, the beatfrequency produced by adjustment of the remote control box frequency toa value suitable for receiving this frequency would be the same as thestation frequency itself, viz. 750,000 cycles, and there will thereforebe interference between the beat frequency and the direct antenna signalfrequency which will be manifested by sqeals and bowls on the receiveras this particular 750,000 cycle transmitting station is being tuned inby manipulation of the remote control box frequency changing element.

Therefore, the receiver R must be tuned and left tuned to a frequencyeither above the broadcast range or else below it.

A further precaution that must be taken in practice is to either designthe circuits of the oscillating tube in the remote control box C in sucha way as to provide an oscillating current in the light lines of puresine Wave form devoid of harmonics, or on the other hand utilize theentire automatic electrical beat tuning principle in such a way that ifthe remote control box C does generate harmonic frequencies of itsfundamental oscillation that these harmonics will not produce heatfrequencies with any other antenna signal equal to that frequency towhich the radio receiving set has been left tuned. For, obviously, ifthis occurs two or more signalsor programs would be heard at the sametime, one being the beat frequency of the control box tubes fundamentalagainst the frequency of one station on the antenna, and othersresulting from the production of the same beat frequency through theintermixing of the harmonics from the control box with stations usinghigher frequencies.

I have discovered, however, as regards the reception of broadcastprograms (200 to 550 meters wave length) wherein the problem as abovestated, is particularly diflicult on account of the relatively wide bandof frequencies employed and their closespacing, that this possibility ofharmonic interference with its consequent reception of more than oneprogram at the same time is avoidable. This circumstance arises out ofthe fact that for the usual American broadcast reception, the ratio ofthe highest frequency required from the control box C to the lowestfrequency so required is substantially less than two; and further thatbroadcasting receivers are commonly designed to be responsive or tunableto frequencies slightly below and slightly above the extreme frequenciesemployed for broadcast transmission.

In applying the tuning feature of the invention to the reception of wavelengths commonly used for broadcast transmissions, viz. 200 to 550meters, I am able to use any ordinary broadcast receiver without makingany change therein whatever. In fact, such receivers are ideally suitedfor the application of the methods of my invention, since, as juststated, they are tunable to frequencies slightly above or slightly belowthe spectrum of broadcast frequencies. Thus, a typical receiverprimarily designed to operate on wave lengths from 200 meters up to 550meters-.

will be found to tune to 200 meters at for instance 10 on the dial ordials and to 550 meters at say 95 on the dial or dials. This leaves fromO to 10 at the lower end of the dial scale and 95 to 100 at the upperend of the scale in which regions no broad- .casting is normally heard.In using such a receiver, according to the methods of the presentinvention, therefore, the operator tunes his receiver either to a dialsetting at the top of the scale, for instance, 100 or to the bottom ofthe scale, for example 0 since at neither of these settings will he hearbroadcast signals direct from the antenna through the mixing box M,Figure 2. The frequency to which he thus tunes-his receiverwill be thebeat frequency that will be employed in the remote control tuningoperation as above described.

For example, suppose the dial or dials of the receiver are turned to theextreme top of the scale, viz. 100. The receiver then may be tuned tosay 600 meters or 500,000 cycles which is 60,000 cycles below thelongest broadcast wave length used. In order to tune in the longestbroadcast wave length used that is, a 540,000 cycle station by theremote control method of my invention, the operator merely rotates thevariable condenser in the control box C, Figure 2, until the frequencygenerated by the oscillating tube in the control box is 1,040,000cycles. The beat frequency then produced will be 1,040,000 cycles minusthe station frequency of 540,000 cycles or 500,000 cycles which is thefrequency to which the receiver has already been tuned. If it is desiredto tune in a station of 400 meters wave length equivalent to 750,000cycles, this station will be heard on the receiver when the remotecontrol box frequency is adjusted to generate a frequency of 1,250,000cycles whereby the beat frequency produced is again 500,000 cycles whichwill, of course, be amplified by the receiver since the latter is stilltuned to hese 500,000 cycles at 100 on its dial. Similarly if it isdesired to hear a 200 meter station (1,500,000 cycles) which is theshortest wave length commonly used for broadcasting in this country, theremote control frequency is set to 2,000,000 cycles and again the beatfrequency will be 2,000,000 minus 1,500,000 or 500,000.

Therefore, it will be noted that for broadcast reception, as abovedescribed, the control box circu ts need only be designed to producefrequencies from 1,040,000 up to 2,000,- 000 cycles, a ratio less than 2to. 1. This condition prevents the previously mentioned diiiiculty ofmultiple program reception which may arise from harmonics generated inthe remote control unit, since the first harmonic of the latter hastwice the frequency of the fundamental and the next harmonic three t mesthe frequency of the fundamental whereas, as just shown, 1,040,000 isthe lowest control box fundamental required and its first harmonic,namely 2,080,- 000 cvcles is 80,000 above the highest control boxfrequency needed and cannot produce a beat frequency of 500,000 cyclesto which the radio receiver is left tuned'with any broadcast stationsince these only use frequencies up to 1,500,000 which exteremefrequency would produce a beat of 580,000 cycles with the control boxharmonic just referred to and this will not pass through the receiver.

If the receiverdials are turned down to 0 instead of up to 100 then thereceiver will be tuned below the broadcast range, say to 1,600,000cycles, and the control box frequencies required to cover the broadcastband will range from 3,100,000 to hear a 200 meter (1,500,000 cycle)program up to 2,140,000 to hear the longest wave stations using atransmitting frequency of 540,000 cycles. This again is a variation incontrol box frequency of less than two to one so that harmonicinterference is easily avoided.

A' unique feature of the method of electrical tuning of the receiver R-according to the present invention, is that radio telephone andtelegraph stations may be received even though these stations aretransmitting on frequencies far different from those for which thereceiver that is being employed is primarilv designed. Thus, if anordinary broadcast receiver suitable for from. 200 to 550 meter lflreception is uesd, its wave length range may be extended to practicallyany degree with out making any changes in it if the present method ofremote control tuning is employed. fill that is required is to arrangethe remote control tuning circuits of the oscillating tube at f] tocover the wider band of frequencies. That is. a meter station (0,000,000cycles) can be heard on the regular receiver if the control boxfrequency is adjusted to say 0,500,000 cycles because the beat frequencywould then be 500,000 cycles which corresponds to the receiver tuningwhen its dials are set at 100 on the scale or scales.

The same principle obviously applies to the reception of longer "wavestations such as 2,000 or 3,000 meters. When thus extending the range offrequency reception, due c0nsidera tion must be taken of the possibleinter ference difficulties hereinbefore described. The prevention ofsuch interference will be readily accomplished by any one skilled in theart through an understanding of the causes of such interference ashereinabove euplained.

it!" @251 m of regulating signal strength or column Referring now in ageneral way to the feature of the invention which deals with theregulation of signal strength or volume, this is accomplished by thesimple expedient of regulating the intensity of the oscillationsimpressed upon the electric light lines at the remote control point.

ft the oscillating energy from the remote control box U is strong, thebeat frequency produced in the mixing box M by the combination of thecontrol. box frequency with the antenna signal frequency will be oflarge amplitude and produce loud response through the radio receiver,whereas. if the oscillation delivered from the control box to thelighting lines is wealr, the beat frequency produced in the mixing boxwill be correspondingly weal: and hence the signal strength from theradio set diminished.

The regulation of the amplitude of oscillations impressed upon the linesfrom the remote control box may be accomplished in varliouslways whichwill be described later in total fil et/i011 of switching receiver onand off The third function of the remote control operation namely thatof switching the radio receiver on or off, necessarily involves more orless difficult problems since there are no connecting wires between theremote control point and the radio receiver other than the wire of thehouse lighting circuit. However, it is very desirable to use these lightlines for the purpose of remote control because in the first place theyare already installed in the house and, therefore, make for simplicityand convenience, and secondly by confining all of the operating andcontrol currents within these wires it is possible to preventdisturbances in radio receivers in other houses in the neighborhood orin other apartments in the same apartment building. The practicalhandicaps to remote control switching of the radio receiver under theseconditions are as follows z- I. The most important circumstance is thatswitching actually requires the throwing of a switch. This requires manytimes the power required for the beat frequency tuning even though avery delicate relay with movable armature is employed to open and closethe circuit. The tuning principle described can be effectively utilizedwith a few hundredths of a volt delivered from the control box to themixing box because the tuning phenomenon is entirely electrical incharacter whereas the operation of a relay switch which is a mechanicaldevice with weight and friction may require several hundred times asmuch voltage.

II. It is not difficult to send enough power aver the two light wiresfrom the control box C to the mixing box M when there are no lights orother electrical appliances connected across the lines but when lamps asat nighttime, or when electric refrigerators, oil burners, electricstoves, etc. are turned on they are in fact connected between the twolight ing or power lines in the house and constitute a virtual shortcircuit on the line to any current which one might ordinarily attempt tosend over the lines from the control box 0. This short circuiting effectordinarily would prevent the delivery of enough power from the remotecontrol unit C to the radio receiver R and the mixing box M toaccomplish the desired switching. It is necessary, therefore, to employmethods and means which will accomplish the switching of the radio setwithout any efiect from the turning on or off of lamps or otherelectrical devices in the house.

III. The fact that the electric light lines are grounded in nearly everybuilding in accordance with the fire underwriters requirements alsopresents difficulties from the switching standpoint because such groundconnections may also produce short circuiting effects when certainarrangements for remote switching are attempted.

According to the present invention, one of the methods and means forovercoming the difiiculties to be noted may be explained by reference toFigures 3 and 3a of the drawmes.

By reference to Figure 3 it will be ob served that the remote controlbox C and the mixingbox M are shown as being connected with the varioushouse service lines L which include various branch circuits for lamps,motors, etc. across them, the lamps being des ignated as L the motor asL and an electric stove or the like being designated as L The groundingon the electric circuit system is shown at G, such grounding generallyexisting at the main switch and service meter of all buildings. InFigure 3a I have shown diagrammatically certain apparatus that iscontained within the mixing box and the remote control box whichapparatus is connected to theelectric light lines L at 9 and 10. At theremote control point, that is, within the remote control box C, there isshown an oscillating vacuum tube T associated with circuits comprising agrid inductance 11 inductively coupled to plate inductance 12 and withbias resistor 13 by-passed as usual by the condenser 14. The tube T issupplied with power for its filament and plate circuits from the' lightlines according to methods well known in the art. At the point where theradio set and mixing box M are located I employ and have shown in Figure3a a vacuum tube detector T with its conventional gridleak 15 andcondenser 16. The grid-leak condenser vacuum tube method of detection isused because it is one of the most sensitive known methods of detection.The detector tube T is connected on its-grid or input side netic forcewhose value depends upon the magnitude of the detector tube platecurrent.

Now in the method of remote switching which is illustrated in Figure 3a,the circuits of the remote control oscillating tube '1 are so designedthat oscillating current is generated having a certain predetermined andfixed frequency and the circuit of the detector tube T in the mixing boxM is designed to be resonant with the frequency generated in the remotecontrol box C. Thus the circuits of the control box C are in tune withthose of the mixing box and if these two tuned circuits are coupledtogether, current oscillating in the control box circuit will readilyproduce a similar oscillating current in the mixing box M. I havediscovered that by a proper choice of frequency and with certain circuitarrangements to be described more in detail later, the coupling justre,- ferred to between the control box circuit and the mixing box may besuitably provided by the lighting circuit itself to which both thecontrol unit and'the mixing box are connected and I provide thiscoupling in such a way that the two wires of the lighting circuit aremade to act substantiallylas a single co'nductor. The entire switchingsystem thus comprises essentially an oscillating circuit havingso-called unilateral connection to a distant resonant circuit responsiveto it' through the unilateral connection provided. The two lightingwires LL are caused to act as a single conductor for the controlfrequencies used by means of the condensers 20 and 21a, Figure 13a,connected across them, these condensers being located respectively inthe mixing box and in the remote control box. The inherent capacityindicated at 21 between the lines also contributes to this effect,especially if the wires are closed together as in the BX type house wireor run for considerable distances in the house, since both proximity ofthe two wires to each other and a great length of double conductorconspire to increase the inherent line to line capacity referred to.

It will now be clear that lamps or other electrical appliances connectedacross the lines thereby causing more or less of a short circuitingeffect between the lines as already explained, will produce nodeleterious effect whatever upon the oscillating current passing overthe lines from the control box, since these two lines now act as asingle conductor for the high frequencies used for the remote controloperation. Another concomitant feature of importance in thus utilizingboth sides of the line as a single one-way conductor resides in the factthat through the condition described two wires are virtually placed inparallel to carry the control current. This reduces the resistancetofthe unilateral connection as well as its inductance, whichcircumstances, in lines commonly met with in practice contribute tolessen the attenuation of the control currents and hence to thedevelopment of greater voltage delivered from the control box over theline to the mixingbox detector tube T'.

Of course, physically there cannot be a transfer of energy from theoscillating control tube to the mixing box over one wire alone. Theremust be a return circuit. In the present invention this return circuitis provided, at least in part by the stray capacity between the two setsof apparatus. This capacity is indicated at 22 in Figure 3a and arisesthrough the roximity of both the apparatus at the contro point and theradio set and associated mixing box to other wires in the building,steam or water pipes, walls. fioors, gas pipes, etc. It may beincreased, if

desired, by the use of small condensers connected between the circuitsof the mixing box and the water pipe or other ground connectionregularly used at the radio set.

With the switch 9 at the remote control box open no oscillating voltageis impressed on teeter tube T of the mixing box is relatively large, forexample three milhamperes. Now when the switch 9 at the remote controlpoint is closed, an oscillating voltage is impressed on the light lines,and hence upon the circuits of the detector tube which will respondreadily to this oscillation since they will have been previouslydesigned to be resonant to the switching frequency used. immediatelythis happens, the detector tube plate current is reduced in accordancewith well known laws of such detector action. in practical designs ofapparatus embodying my invention, the plate current drops from aboutthree inilliamperes to 0.2 or 0.3 milliamperes. llf the spring on thearmature of relay l9 is adjusted so that a current of say it or 2.0inilliainperes will cause the armature to be drawn up against the poleface of the relay magnet, then before the switching voltage comes on andthe plate current is three milliamperes the relay contacts 19a will beopen; but when the switching voltage is applied and the detector platecurrent drops to say 0.3 milliamperes the magnet of the relay willrelease the relay armature whose spring will cause the contacts 19a toclose. Thus, the contacts 19 may be used to turn the radio set on orelf.

lin using the particular method of switch ing and tuning so fardescribed, it will now he understood that the radio set will remainturned on as long as the relay contacts 19a in the mixing box are closedand that this requires the oscillating switching voltage from thecontrol box to be continuously impressed on the line as long as it isdesired to tune and operate the set from the control point. Thenecessity thus arising of simultaneously im pressing the switchingfrequency on the lines together with the various frequencies requiredfortunii'ig sometimes causes difiiculties, some of which are a seriousoverloading of the detector tube in the mixing box by the strongswitching frequency, the presence of harmonies in the switchingfrequency oscillation which may cause interference with the tuningfrequencies, and the fact that since the switching frequency and thetuning frequencies are both simultaneously being transmitted andreceived with the same apparatus, difficulties of circuit design areencountered. None of these diiiiculties are insurmountable, however, asapparatus already built and operated has shown. Nevertheless, I havefound it generally more satisfactory, when using a selected fixedswitching .frequency as hereinbefore described, to impress thisfrequency momentarily on the line to switch the radio set on and thenimpress it on the line again for an instant to switch the oft. Inasmuchas impressing the switching frequency on the line always causes therelay contacts to close and thereby turn the set on, an auxiliary devicemust be used at the mixing box which will operate by the closing of therelay contacts 19a in such a way that successive closures of thesecontacts will suecessively turn the radio set on and oil. Such anauxiliary device is diagrammatically illus trated in Figure 4.

Referring to Figure 4, the relay windings 19 and relay contacts 19a areshown in connection with an electron'iagnet 23 having a movable ironcore plunger 24: held back against the stop 25 by the compressed spiralspring 26. he pawl 27 hinged at 28 operates the ratchet 29 which isfixed to a shaft 30 which is also fixed to a cam 31. This cam operatesto open and close the spring con tacts 32 and 33. When the relaycontacts 19a are closed the electromagnet 23 is energized from thelighting lines causing the plunger 24 to be drawn into the magnetagainst the stop 23a. In this movement of the plunger it will be seenthat the pawl 27 turns the ratchet 29 and the cam 81 A of a revolutionand thus operates the contacts 32 and 33. When the relay contacts 19aare open, the spring 26 pushes the plunger 24 and pawl 27 back to theiroriginal positions leaving the ratchet and cam, however, and hence thecontacts 32 and 33 in the position they took up on the forward stroke ofthe plunger. Thus, successive forward strokes of the plunger caused bysuccessive closures of the relay contacts 19a results in the alternateopening and closing of the contacts 32 and 33 which, as will be apparentfrom the drawings, re sults in alternately turning the radio receiveroil and on. Briefly, therefore, successive closures of the remotecontrol box switch 9 successively impresses the switching oscillation onthe lines, successively causing the relay contacts 19a to close which inturn successively causes forward strokes of the plunger in theelectroinagnet-ically operated switch with its attendant pawl-ratchetcam operation on the main contacts 32 and 33 for turning the radio setalternately on and off.

\Vhile the foregoing method of remote control switching has been foundto be entirely practical and feasible, an alternative method possessingthe advantage of great simplicity will now be described. In practice Ihave found that it is not quite so universally usable as the method justdescribed, but I have discovered that for all ordinary homes or evenrather large ones, or for apartments, the characteristics of thelighting lines in the building are sufficiently near alike and have suchelectrical properties that this alternative ITIGtlIOClOf switching isalmost universally practical. When using it in very large factorybuildings difficulty is sometimes experienced on account of the greatlength of the wiring circuits or the use of two or three phase supplysystems or three wire systems with grounded center. In such cases thepreviously described switching systrol box are designed to besubstantially responsive to the same degree to all the frequencies to begenerated in the control box for the'purpose of tuning. This design iscarried out with due regard to the electrical characteristics of theaverage house lighting system. Prior to making a more detaileddescription of this method of switching it may be pointed out that arelay is used in the. plate circuit of a detector tube as previouslydescribed but no special or preselected or particular frequency is usedfor switching. The switching is accomplished by the high frequencytuning currents themselves when they pass over the lines from thecontrol box to the mixing box at the receiver. The moment the controlbox is put in operat on as by turning on the current from the lightline, this tube begins to' oscillate, and by the use of suitablecircuits these oscillations are immediately impressed upon the "lightline, and, no matter what their frequency, "are impressed withsubstantially equal magnitudeupon the detector in the mixing box causingthe 1lay"contactstherein to close. This in turn instantly connects theradio set to the line so that it begins to operate. On account of thefact that the design is such that the detector circuits aresubstantially equally responsive to all the tuning frequencies sent overthe line from the remote control box, the relay contacts referred toremain closed and hence the radio set is turned on throughout all thetuning operations conducted at the remote control point by adjusting thefrequencies required for the reception of various stations.

Having now described in a general way the various elements of theapparatus and method employed in the invention to accomplish, (1) remotetuning of a radio receiver; (2) remote controlling of volume; (3) remotecontrol switching of a radio set, the methods and means by which thesevarious objects areconsolidated into practical and useful form will bedescribed.

Figure 5 shows one practical form of the invention in detail, the sameembodying the alternative method of switching and tuning last described.

The remote control box C is shown in dotted lines and contains theremote control cir-- cuits and apparatus while the, radio receiver isdiagrammatically indicated at R and the mixing box and its enclosedapparatus are indicated at M. The house lighting lines L are shown asbeing respectively connected with the remote control box C and themixing box M, and as previously described the house lighting line Lshown at the left hand side of the switch L may run to various otherbranch circuits in the house. One side of the line is shown grounded asindicated at G which is in accordance with standard fire underwritersrequirements.

Referring first to the apparatus contained within the remote control box0, it is pointed outthat the same includes the vacuum tubes T and T thefirst of which is arranged to generate high frequency oscillations, andthe second of which functions as a rectifier tube to supply rectifiedalternating current-to energize the plate circuit of the tube T. Thepower required to operate both of these tubes (in this case assumed tobe alternating current) is obtained from the light lines L through thereceptacle S and plug R. The switch 9 serves to turn the current on oroff in the remote control box. The line current passes through thetransformer comprising the primary winding 36, energizing the secondarywinding 37 which energizes the plates 38 of the rectifier tube T Anothersecondary winding 39 energizes the filament 40 of the tube T and a stillfurther secondary winding 41 energizes the filament 42 of theoscillating tube T. The condensers 43 and 44 together with an iron corechoke coil 45 constitute a filter system to smooth out the rectifiedcurrent from tube T so that the plate current supplied to the oscillatortube T will be substantially non-fluctuating. The circuit of the tube Tcomprises an inductance coil 46 with associated variable condenser 47 bythe adjustment of which the frequency of'oscillation of the tube isvaried. The coil 46 is inductively coupled to the grid coil 48 toprovide the proper feed-back for producing oscillation. The resistor 49is.

tapped at its center and connected as shown and in the conventional wayto the bias resistor 50 and by-pass condenser 51. The oscillating energyin the circuit consisting of the coil 46 and condenser 47 is fed overinto the light line circuit'through the small adjustable or variablecondenser 52 and also through the relatively larger fixed condenser 53.The air core choke coils 54 and 55 prevent the radio frequencyoscillating currents fed over into the light line from entering thetransformer primary 36. The fixed condenser 56 is not always required,but in certain cases is advantageous to at least partially remove highfrequency polarity effects at the plug R. The amount of oscillatingenergy fed into the light lines depends upon the value of capacity usedin the condenser 52. This condenser, therefore, serves as a volumecontrol, reducing the volume when its capacity is decreased and raisingthe volume fttl lift

till

when its capacity is increased. An additional control of volume issecured by slight adjustments of the variable condenser 47 since thischanges the beat frequency at the mixing box to a value slightly awayfrom the frequency to which the receiver is left tuned.

Referring to the mixing box M it will be observed that the same containsthe vacuum tube T previously referred to which functions as a detectorand a second vacuum tube T which functions as a rectifier. The de tectortube T is provided with .a grid condenser 57 and a grid leak 58. Both ofthese tubes, in the illustration shown, are standard three electrodetubes such as the present day standard 227 type detector tubes which arewell suited to the purpose they serve from the standpoint of rectifyingability, detection, sensitivity and freedom from alternating currenthum. These tubes are furnished with power for the operation of theirplate and filament circuits from the light lines L (here assumed to becarrying commercial alternating current) through the receptacle 8 andplug it. The power is supplied through a transformer comprising aprimary winding 59, and secondary winding 60 furnishing power to thejointly con nected plate 61 and grid 62 of the rectifier tube T whichserves to supply rectified alternating current to the plate circuit ofthe detector tube T; another secondary Winding 63 furnishes power tolight the filament 6d of the rectifier tube, and another secondary 65furnishes power to light the filament 66 of the detector tube 'T. Thus,it will be seen that the light circuit current passing through theprimary winding 59 of the trans former just mentioned flows from onlyone wire 67 coming to the mixing box from the plug RQthence through coil68 to and through the automatic voltage regulator 69 and the primarywinding 59 of the transformer. lifter passing through the primary of thetransformer the current then passes to the binding post 6 on the mixingbox assuming, of course, the switch 71 is closed, and then passes toground G which is customarily a steam or water pipe. The current thenpasses through the electric system ground (l -G, Figure 5, the latterground being located at the main house switch L and thereby completingthe circuit to the other side of the line. This circuit arrangement is afeature involving the unilateral connection hereinbefore referred to inconnection with the transmission of oscillating high frequency currentsfrom the control box to the mixing box. it provides a path of lowimpedance for the light line low frequency current but, except for theportion of the circuit comprising the copper line conductors L betweenthe plug It on the control apparatus C and the plug R at the mixing box,it provides a path of very high impedance for the high 0scillationfrequencies generated in the control box which upon their arrival at themixing box are thus prevented from shorting themselves to ground. Theyreach the coil 68 in the mixing box over the line conductors L actingjoint-1y as a single conductor as hereinbefore explained, the lattereffect being enhanced by use of the condenser 72 in the mixing box toincrease the capacity between these lines. They then return to thecontrol box circuits partly by virtue of stray capacity as previouslyexplained but more particularly by passing through the coil 68, thencethrough the condenser 73, thence to the mixing box ground G and back tothe control box circuits through the light circuit ground G at theswitch L and the light line circuits L.

In thus passing through the coil 68, the high frequency currents fromthe control box induce a voltage in the coil 74. which is inductivelycoupled to the coil 68, and thus actuate the grid of the detector tube.The design of the coils 68 and 74, together with the adjustment of thecapacity 73, must be given special attention depending upon the range offrequencies to which it is desired to have the mixing box circuitsresponsive. Thus for the remote control operation of this system tocover the usual broadcast range of 200 to 550 meters, I construct thecoil 68 by winding sixty-five turns of #32 gauge wire on a one'andone-eighth inch diameter bakelite tube, and I place the coil 74 insidethis tube. I wind the coil 74 on a diameter rubber rod in which areturned nine grooves spaced 5/64" apart each groove containing eightyturns of #34; gauge Wire. The antenna connection 75 is tapped into thiscoil 74, as shown, at its center turn. In connection with this coilsystem and the other circuit elements which have been used in practicalforms of the apparatus for broadcast reception, the size of thecondenser 73 has been found to be best at a capacity of 250micro-microfarads.

The plate 76 of the detector tube T is c0nnected, as shown, to the radiofrequency choke coil 77, thence to the relay magnet winding 19, andthence to a point on the resistor 78 from which pointa suitable value ofdirect current voltage is taken to operate the plate of the detectortube and relay. The condensers 7 9 and 80 in combination with the ironcore choke coil 81 comprises a filter for smoothing out the rectifiedalternating cur rent impulses delivered from the rectifier tube T allaccording to present day practice in the art. It will be seen that theplate of the detector tube is also connected to a condenser 82, whichfrom the binding post 3 on the mixing box leads to the binding post 1 onthe radio set R, this binding post 1 being the post ordinarily used forconnecting the antenna A to the set. The ground binding post 2 of 1" theradio set R connects to the binding post 4: on the mixing box which inturn leads back to the cathode of the detector tube T in the mixing boxand to ground G through the fixed condenser 83. The power supply cord 84customarily attached to the radio set and ordinarily plugged into a wallsocket or other socket on the electric light system of the house is hereplugged into the mixing box by means of the plug connector 85 andreceptacle 86. The only connection to the electric light system,therefore, is through the mixing box plug R, the power circuit to theradio set running from this point through the two radio frequency chokecoils 87 and then through the relay contacts 19a which are held closedby the spring 19?) unless sufiicient detector tube (T) plate currentflows through the relay windings to pull the armature of the relay upand thus open the contacts at 19a, and hence open the power supply tothe set, turning it off.

As previously stated, the coils 68 and 7-1 and the condenser 73 must beproportioned with some care and due regard to the variousradiofrequencies that are to be handled in the entire radio system. Inthis respect the aim of the constructor or designer will be to soarrange the coils and condenser referred to that substantially equalradio frequency voltages will be impressed upon the grid of the detectortube T for all of the frequencies generated in the remote control box aswellas all the frequencies which it is desired to receive from theantenna A. It will be clear to those skilled in the art that this resultwill also be effected to some extent by suitable design of theoscillating circuits and the couplings in the control box.

Operation of system In practice the mixing box M is placed at aconvenient location adjacent or near to the radio set R and the'powercord 8485 is plugged into the receptacle 86 of the mixing box. Theantenna binding post 1 of the so; is connected to the bindin post 3 ofthe mixing box, and the ground binding post 2 of the receiving set isconnected to the binding post 4 of the mixing box. The plug R of themixing box is then plugged into the socket or outlet convenient to theradio set and the mixing box is then ready to function in connectionwiththe control box-C. The control box C is then carried to any point in thehouse or building and its plug R plugged into any convenientsocket oroutlet. Thus the control box C may be moved from point to point in thehouse or building for controlling the radio receiver R from any desiredpoint over the light lines L.

When the mixing box M is connected with the receiving set R in themanner referred to, the power switch on the set itself is turned on andthe switch 71 in the mixing box is closed. The latter immediatelysupplies light line power to the tubes T and T (The mixing box plug Rmust be properly poled by trial. That is, if the tubes T and T do notlight up when switch 71 is closed the plug R must be reversed.) As thesetubes heat up to operating temperature, the plate current of thedetector tube T flowing through relay magnet winding 19, will attractthe relay armature and break the relay contacts at 19a so that the radioset is turned off.

The tuning dial or dials on the radio set are tuned or turned to somesuitable setting such as 100 or to zero scale reading. The receiver isleft at this setting.- The remote control unit C ma now, as previouslyindicated, be plugge into any socket in the house, and by turning theswitch 9 of the controlcbox the circuit from the plug R is c osed to therectifier tube T. This starts the delivery of the plate current to thetube T and the latter starts to oscillate. The oscillating current thusproduced passes over into the light line through condenser 52, arrivesat the mixin box through plug R and in passing throug coil 68 induces avoltage in coil 74 which is impressed upon the grid of the detector tubeT. Immediately this happens, the plate current of the detector drops,and sincethis current passes through the relay windings 19, the relay isde-energized permitting the spring 19?) to pull the relay armature backand close the contacts at 19a. These contacts in closing complete thepower line circuit to the radio set, thus turning the latter on. Sincethe coil system 68, 74 and condenser 73 are so de- The frequency of theremote control unit oscillation is, of course, regulated by the variablecondenser 47 therein so that manipulation of this condenser results inthetuning in of various stations on the receiver all as hereinbeforeexplained.

When. the remote control unit is turned off by means of its line switch9, the plate current of the detector tube T in the mixing box M andhence the relay current increases promptly to its normal value, breakingthe relay contacts 19a which turns the radio set off.

In the practical operation of this system there is delivered totheqnixing box M from the remote control box 0 an oscillating volt- Page many times greater than that produced in the mixing box by anincoming signal from the antenna. This has the effect of sensitizing thedetector in the mixing box and permits tube and relay adjustments to bemade therein which will not permit the turning on or off of the radioset by the lesser energy of the antenna signal alone. Loud crashes ofstatic will occasionally cause the relay contacts to open orclose butthis effect is sporadic and of momentary duration so that the effectsproduced are no more deleterious to the operation of the radio set thanare commonly experienced under heavy static conditions. I have foundthat the sensitiveness of the entire receiving equipment to weak signalsis not impaired by the interposition of the mixing box between the setand the antenna when using the present remote control system ofoperation. I have also found that the selectivity of the receivingsystem is not impaired. The reasons for these two circumstances will beclear to those skilled in the art from an understanding of the method ofoperation of the system as described. The practical form of the circuitsand apparatus herein described is especially typified by its simplicity,ruggedness, ease of manufacture, use and portability.

The detector tube T in the mixing box M serves not only to operate therelay but also rectifies the combined antenna signal current and remotecontrol light line tuning currents to produce the beat frequency currenthereinbefore referred to, which beat frequency current is passed to theradio receiver through the condenser 82 since it is prevented frompassing through the relay circuit by the high frequency choke coil 77.

A modification of the invention is shown in Figure 6 of the drawings.The form of invention shown in this figure involves'the use of aselected, fixed, and predetermined frequency generated at the controlbox and used for the switching of the radio receiver on or off, incombination with the use of other high frequency currents also generatedat the control box and used for the tuning of the receiver. Referring toFigure 6, it is pointed out that only the essential elements of theinvention are shown. That is to say, such conventional elements,accessory thereto, such as power transformers, rectihers, filters, etc.for energizing the essential elements are for sake of clearness,omitted, since such ascessory elements are similar to those shown inFigure 5 and fully described in connection therewith.

The circuit and apparatus elements of the remote control box areindicated generally at C, and those of the mixing box are designatedgenerally at M while the radio receiver is designatedat R. The controlbox l3 contains an oscillating vacuum tube '1' l with grid circuit coils90 and 91 in series and inductively coupled respectively to the platecircuit coils 92 and 93 thus providing the necessary feed-back forproducing or generating oscillations. The coil 92 is shunted by a fixedcondenser 94 and the coil 93 is shunted by the variable condenser 95.The plate voltage required for the oscillation of the tube isconventionally supplied at the points +13 and -13 and the filament ofthe tube is also lighted in the conventional way. The tube T is used togenerate various frequencies. One such frequency is determined by theconstants of the circuit comprising the condenser 94, coil 92, and coil90. This frequency is selected and produced by suitable design of saidcircuits for the purpose of switching the radio receiver R on or oft.Other frequencies are generated by the same tube T by means of theassociated circuits comprising variable condenser 95, coil 93 and coil91. Such latter frequeni cies are used for tuning the radio receiver inaccordance with the principles heretofore described. The entireapparatus at the control point is connected to the electric lightcircuit L, the point of connection involved in the operation of thecontrol box elements here under discussion being shown at 96 through thesmall variable volume control condenser 97 and switch 98. Besides theswitch 98, there are two other switches 99 and 100 located in thecircuits as shown. All three of these switches are mounted on a sin--gle shaft so that they operate simultaneous ly. The arrangement is such,however, that switches 99 and 100 open when the switch 98 closes. Itwill be seen that when switches 99 and 100 are closed (and hence switch98 opens) the tube T in combination with the circuit elements 91, 93 and95 generates high frequency currents suitable for carrying on the tuningof the receiver and regulating its volume through condenser 97, and thatthe circuits comprising the elements 90, 92 and 94 will not then beoscillating because they are short circuited by the switches 99 and 100.When the last mentionedswitches are opened, however, and switch 98closed, the short circuits are removed from the circuits of 90, 92 and94, and they will generate the particular frequency for which they aredesigned, which frequency will be impressed directly on the light linethrough the switch 98 which now shorts out the small variable condenser97. Thus, the switching frequency The mixing box M contains the detectorto the grid of the detector tube in the mixing box are difierentlyarranged. As shown, these circuits now comprise the inductively coupledcoils 102 and 103, both respectively connected in series with theinductively coupled coils 104 and 105. By suitable design all these coilsystems, in connection with the capacities 106 and 107, in accordancewith known principles and methods, are made resonant or tuned,definitely to the frequency generated in the control box for the purposeof switching the radio receiver on or off, while the coil system 102,103 is made responsive to all frequencies which are picked up on theantenna A or which are generated in the control box for the purpose oftuning. The switching frequency is selected to be different from any ofthe last mentioned antenna or tuning frequencies. It will now beseenthat when the switching frequency is impressed on the line at thecontrol box in the manner previously explained, the circuits 104 and 105at the mixing box being tuned to this switching frequency will respondwith great strength and stron ly affect the detector tube T in thecontrol box, causing a sharp and pronounced decrease in its: platecurrent which flows through the relay 108 thus allowing its contacts toclose. The closure of these relay contacts 109 energizes the solenoidplunger magnet 23-24 from the light line source at 101 through hi hfrequency choke coils 110 as shown, whic in turn operates thepawl-ratchet-cam device 27-29-31 in the manner described in connectionwith Figure 4, and hence turns the radio set on or off as will beobvious from the drawings.

On the other hand, when the switching current from the control box isremoved from through the condenser 111 and back to the detector tube Tthrough the wire connection 112. The choke coil 113 prevents highfrequency currents from passing through the relay windings and forcesthem to pass to the.

radio receiver.

In the operation of this modification of the turned off by againimpressing the switching frequency from the control box upon the linesby manipulation of the triple switch 98- 99100.

While the attached drawings and the above description have referredgenerally to the use of commercial alternating current house light orpower service, it will be understood that the novel features of theinvention are not at all restricted to alternating current supplysystems, but are equally useful and readily adaptable by anyone skilledin the art to direct current lighting or power systems and the claimsfollowing have been drawn accordingly.

I claim 1. The method of controlling the entire operation of a radioreceiver over the electric light lines from a remote control point alongsaid lines, which includes selectively receiving various desiredsignals, regulating the strength of said signals, and turning thereceiver on or off, which consists in transmitting high frequencycurrents over the said light lines from said remote control point to thepoint where the receiver is located, mixing said high frequency currentswith said desired signals, rectifying the currents resulting from saidmixing, regulating the strength of said high frequency currents andrendering the receiver inoperative by cutting oif said high frequencycurrents.

2. The method of controlling the operation of a radio receiver from adistant point, over a power line to which the receiver is connected,which consists in transmitting over the power line an electricalimpulse, supplying operating power to the receiver by actuating a switchby means of said impulse, then transmitting over the power lines currentof variable high frequency, mixing said variable high frequency currentwith desired signal currents, rectifying the currents resulting fromsaid mixing, regulating the strength of the said variable high frequencycurrent, and finally turning off the power supply to the receiver byagain transmitting an electrical impulse over the power line.

3. In the art of radio signalling, a system for the entire remotecontrol operation of a radio receiver including the selective receptionby said receiver of signals from transmitting stations of any wavelength, the regulttl all

llti lation of the strength of such signals, and the switching of thereceiver on or off, all from a point other than at the receiver itself,comprising in combination, an electric light or power line system, aplurality of interconnected apparatus means adjacent the receiver, aplurality of auxiliary interconnected apparatus remote from thereceiver, an antenna, a ground connection, connections between saidmeans adjacent the receiver, and both the light line system and thereceiver, connections between the means adjacent the receiver and boththe antenna and the ground, and connections between the auxiliarv meansremote from the receiver to said light or power line system, means atthe remote con- 'rol point constituting a generator of high t;ttrequency currents, and other means also located at the remote controlpoint including a switch device which permits impressing the said highfrequency currents upon the light lines at the said remote controlpoint.

l. l t leans for operating radio receiving apparatus from a remote pointover electric light or power lines with which said receiver isconnected. comprising the combination with the receiving apparatus andthe house lighting lines having a plurality of outlets, of a controldevice located at anyone of said outlets for generating high frequencycontrol currents, the said device having means to cause the receivingapparatus to receive and render intelligible signals intercepted fromtransmitting stations using various wave lengths, to regulate thestrength of such signals, and to switch the operating power to thereceiver on or off, the said light or power lines being adapted tofurnish operating power to both the receiver and the said control deviceand also adapted to transmit said high frequency control currents fromthe control means to said receiving apparatus.

5. The combination with the house lighting lines of a radio receiver anddetecting apparatus including an antenna system, said receiver andapparatus being electrically connected with said house lighting lines,and a device for remotely controlling the operation of said receiver anddetecting apparatus adapted to be connected to any point in the houselighting lines, said device including means for generating andimpressing high frequency currents upon said lines to cause the saidreceiver to render intelligible signals in tercepted from radiotransmitting stations using various wave lengths, the said device alsoincluding means for regulating the strength of such intercepted signals,and means at the remote control point for switching said hiofh frequencycurrents on or off to the light lines to turn the operating power fromthe light lines to the receiver on or otii.

litleans for remotely controlling a radio receiver apparatus having anantenna system, over electric house lighting or power lines with whichsaid apparatus is connected. from a point along said lines, to cause itto selectively respond to various distantly transmitted radio signalswhich are intercepted by the antenna system; comprising, a devicelocated at the control point along said lines and having a plurality ofmeans for generating variable high frequency currents and impressingsaid currents upon said lines, means for causing said house lines tocarry said high frequency currents as a single unilateral conductor fromthe point of remote control to the point at which the receiver islocated, and means respectively connected to the receiver, to theantenna and to the house lines and responsive to all of the aforesaidvariable frequencies transmitted over the house lines from the controldevice and also responsive to the signal frequencies received by theantenna system.

7. A system for controlling a radio re ceiver over house lighting orpower lines to which said receiver is connected including meansassociated with the receiver for simultaneously receiving variable highfrequency currents transmitted thereto over the power lines and radiosignals from the antenna system, apparatus remote from said receiverhaving means for generating high frequency currents, means for couplingsaid apparatus to said lighting or power lines for impressing saidvariable high frequency currents thereon, said variable high frequencycurrents being transmitted to said first mentioned means for controllingenergization of said receiver and heterodvning with the incoming signalfor controlling the tuning'and regulating the signal strength of saidreceiver.

8. A method of controlling a radio receiver over the house lighting orpower lines which consists in generating variable high frequencycurrents at a point remote from the receiver, impressing said highfrequency currents on said lighting or power lines, whereby saidcurrents heterodyne at the radio receiver with radio signal currentsintercepted by the receiver to produce a super-audible beat frequency atthe receiver for controlling the energization, tuning, and signalstrength of the receiver.

9. A system for controlling a radio receiver over house lighting orpower lines to which said receiver is connected, including meansassociated with the receiver for simul taneously receiving variable highfrequency currents transmitted thereto over the power lines and radiosignals from the antenna system, and a remote control apparatus havingmeans for generating high frequency currents, means for coupling saidapparatus to said lighting or power lines for impressing said variablehigh frequency currents there on respectively for switching the powersupmeans associated with the receiver for re-' ceiving variable highfrequency currents transmitted thereto over the power lines and radiosignals from the antenna system, means for heterodyning the variablehigh frequency currents and radio signals, and apparatus connected withthe said lighting or power lines at a point remote from said receiverfor producing high and variable frequency currents which are transmittedover said lighting or power lines from the control point to said firstmentioned means.

11. A system for controlling a radio receiver over house lighting orpower lines to which said receiver is connected includin meansassociated with the receiver adapted for receiving variable highfrequency currents transmitted thereto over the power lines and alsoreceiving radio signals from the antenna system, said means comprisingmeans for mixing said high frequency currents with radiant energyreceived b the antenna system, and means for rectifyingv the currentresulting from said mixing; and means for producing oscillating highfrequency electrical current at a point remote from said receiver andtransmitting the same over light or power lines to said first namedmeans to selectively render said receiver operat1ve or inoperative.

12. A system for selectively receiving various radio signals on areceiver connected with house lighting or ower lines including means forproducing high and variable frequency electrical currents from a controlpoint on said lines remote from the receiver and transmitting the sameover said lines to the receiver, means at the receiver for collectingsignal energy from the antenna system and high frequency energy from thehouse lighting or power lines, means for mixing said ener with said highfrequency currents, and means for rectifying the energy resulting fromsaid mixing.

13. A system for selectively receiving various radio signals comprisinga radio receiver connected to the house lighting or power lines, controlapparatus remote from the receiver and having means for generating andimpressing high frequency currents on said lines, and means at thereceiver for intermixing high and variable frequency currents and signalenergy intercepted by sald receiver, and means for producing highfrequency super-audible beats by rectifying the current resulting fromsaid intermixing, and ineans for impressing said beats upon the radioreceiver to accomplish the selective reception aforesaid.

14. A system for selectively receiving various radio signals comprisinga radio receiver connected to the house lighting or power lines, controlapparatus adapted to be connected to the said lighting or power lines ata point remote from the receiver and having means for generating andimpressing high frequency currents on said lines, means at the receiverfor superposin said high frequency currents from the lig ting or powerlines on the signal currents intercepted by the receiver, means forrectifying both of said currents at the receiver to produce a rectifiedresultant high frequency current equal in frequency to the differencebetween the frequencies of the two said superposed currents, and meansfor impressing said rectified resultant current upon said radioreceiver.

15. In a radio receiver control system, means for switching a radioreceiver on or off over the electric light lines from a control pointalong said lines, comprising a plurality of means at said control pointfor generating and impressing upon said lines high frequency currents, aplurality of means at the receiver, auxiliary and external thereto,connected to said light lines for receiving said high frequency currentsover said light lines, and a separate plurality of means at thereceiver, auxiliary and external thereto, responsive to said highfrequency currents in such manner as to effect the switching on or offof the said radio receiver.

16. In a remote control system for operating radio receivers, means forswitching a radio receiver on or off over an electric light line towhich said receiver is connected, from a point along said line,comprising means for generating a fixed predetermined high frequencycurrent at the said control point, means for impressing said currentupon said line at the control point, means at the receiver, auxiliar andexternal thereto, also connected to said ight line and electrically resonsive to said high frequency current received by' said auxiliary meansover said light lines, and means connected to the said auxiliary meansto accomplish the said switching on or off of said radio receiver.

17 A system for the entire remote control operation of a radio receiverincluding the tuning of said receiver to receive and reproduce signalsfrom transmitting stations of any wave length, the regulation of thestrength of such signals, and the switching of the receiver on or off,from a point other than at the receiver itself, comprising incombination an electric light or power line system, a plurality ofinter-connected apparatus means adjacent the receiver, a plurality ofauxiliary inter-connected apparatus means remote from the receiver, anantenna, a ground connection, conn ptions between said auxiliary meansadjacent the receiver and both the light line system and the receiver,connections between the auxiliary means adjacent the receiver and boththe antenna and ground, and connections from the auxiliary means remotefrom the receiver to said light or power line system, wherein a portionof the means remote from the receiver is a generator of a high frequencycurrent of fixed and predetermined frequency used for switching thereceiver on or off, means at the remote control point constituting agenerator of high frequency currents of adjustable frequency used fortuning said radio receiver and regulating its volume, and other meansalso located at the remote control point including a switch whichpermits impressing upon the light lines at said remote control pointeither'the said switching frequency or the said tuning frequencies.

In testimony whereof I hereunto aflix my signature.

ALBERT S. BLATTERMAN.

